I don't know synecdoche from metonymy, but I do know that two-thirds of a pun is PU! :-)
To / Two / Too
Higgledy-Piggledy
Paronomasia,
Play on words otherwise
Known as a pun,
Keeps us in stitches with
Double-entendreous
Homophones, words which can
Generate fun.
There are three words pronounced [tu] in English: to/two/too. Notice how the meanings of the following sentences change depending upon which form you use.
"Balls!" said the queen. "If I had ___, I'd be king." The king laughed ___; he had ___!